Yarns composed of multiple filaments are traditionally produced by melt-spinning techniques whereby a melt-spinnable polymer is extruded through relatively small-sized orifices in a spin pack to form a stream of filaments which are substantially immediately solidified in a quench cabinet and converged after solidification to form a yarn composed of multiple filaments. The yarn is thereafter continuously taken up by a high speed winder to form a generally cylindrical yarn package. Depending on the intended end use, the yarn may be flat (undrawn) or may be subjected to a drawing step prior to being taken up to form the package.
During take-up, the yarn end is guided through a traversing arm associated with the high speed winder. The traversing arm reciprocates at relatively high speed linearly parallel to the longitudinal axis of a rotating yarn package core. As a result, the traversing arm causes the yarn end guided thereby to be wound in alternating layers of reverse helical directions about the core as the yarn package is "built" (i.e., as the radial dimension of the yarn package increases due to the yarn end being wound thereabout in alternating reverse helical layers).
Because of the linear traversing arm associated with automated winders, it has been the conventional wisdom in this art that only a single yarn end may be wound around the yarn package core. That is, it has been considered technically unfeasible to wind at multiple yarn ends around a single yarn package core since the traversing arm was thought to cause intermingling to occur between the multiple yarn ends. Such yarn end intermingling would thereby prevent them from later being separately unwound from the yarn package and used individually during downstream processing (e.g., as might be needed for beam warping, knitting or like operations requiring the use of multiple yarn ends).
Contrary to the conventional wisdom in this art, it has now been discovered that multiple yarn ends may be wound concurrently about a single yarn package core using conventional high speed winders without twisting occurring between the individual yarn ends. As a result, according to this invention, the multiple yarn ends comprising the yarn package may be individually unwound from the package and separated for purposes of downstream processing (e.g., beam warping, knitting and like operations).
More specifically, according to the present invention, multiple yarn ends, each of which includes a plurality of synthetic filaments, are converged in such a manner as to form a "ribbon" of the yarn ends--that is, the yarn ends are disposed in a substantially planar side-by-side mutually contacting untwisted relationship with one another. The converged yarn ends in the ribbon are then guided by the traversing arm during winding so as to maintain the side-by-side mutually contacting relationship with one another. In such a manner, therefore, the multiple yarn ends forming the ribbon are wound about the yarn package core in alternating helical turns to form a generally cylindrical yarn package. The individual yarn ends may thereafter be separated from one another by unwinding in a direction substantially tangential to the cylindrical yarn package.
The present invention therefore allows for increased production throughput to occur without requiring the considerable capital expense and/or spatial requirements of additional winders. Thus, greater yarn production may be accomplished using existing spinning systems without additional substantial capital investment.
These and further aspects and advantages of the present invention will become more clear after careful consideration is given to the following detailed description of the preferred exemplary embodiment thereof.